Epsilon Birnbaum–Saunders distribution family: properties and inference

In this paper we introduce a new extension for the Birnbaum–Saunder distribution based on the family of the epsilon-skew-symmetric distributions studied in Arellano-Valle et al. (J Stat Plan Inference 128(2):427–443, 2005). The extension allows generating Birnbaun–Saunders type distributions able to deal with extreme or outlying observations (Dupuis and Mills, IEEE Trans Reliab 47:88–95, 1998). Basic properties such as moments and Fisher information matrix are also studied. Results of a real data application are reported illustrating good fitting properties of the proposed model.     

Estimation of the mean of the exponential distribution with an outlying observation

Given a life testing experiment consisting of n items, n-1 of which have the expected life λ while one could have an expected life λ/α with 0 < α < 1 the problem is. to find a mean square error (MSE) minimizing estimation function. The standard estimators for the homogeneous case (α = 1) overestimate the expected life and their MSE tend to infinity when a tends to 0.

Looking at the estimation problem as an insurance (see Anscombe (1960)) two different “testimators” are compared with respect to their MSE, Numerical results show that an estimation function based on the “Epstein-statistic” x_(n)/[xbar] is the best one.     

Resource smoothing: A cost minimization approach

From the available literature, there seems to be no defined approach to resource smoothing exercise except those attempted by Weist (1967, Management Science, 13, B359-B377) and Burgess and Killebrew (1962, Journal of Industrial Engineering, 13, 76-83). The aim of the smoothing exercise is to achieve optimal resource usage by avoiding high peaks and deep valleys in the project resource profile. The general approach has always been to move some activities with floats in the high peak regions to be started at a later date, and as this is done, the valleys will be filled to smooth the resource profile subject of course to time constraint. If this approach is followed as it is, it would be difficult to determine optimality especially when many resources are involved. A cost minimization approach is envisaged in the present study with no limitation on the number of resource inputs. In a situation where the resources are assumed to have the same value, the cost assigned to each of them should be similar. The method follows the general concept but with a difference; cost of the activity in question is considered. The exercise is continued until all the floats are exhausted. The optimum result would then be the one with the minimum cost profile. From examples used for the evaluation, the results obtained are comparable to those of the above two researchers, and some with better results in the majority of cases.     

Accent on Teaching Materials

Review of International Association for Statistical Education Proceedings: Proceedings of the First Scientific Meeting of the International Association for Statistical Education, Lina Brunelli and Guiseppe Cicchitelli, Editors. U.S. $5 (cost of postage) from International Statistical Institute, 428 Prinses Beatrixlann, 2270 AZ Voorburg, The Netherlands. Includes 49 papers presented in Perugia, Italy, in August 1993; 476 pages. Reviewed by Peter Holmes     

Accent on Teaching Materials

A linear combination test for combining several tests of the correlation coefficient in the bivariate normal distribution is proposed. The linear combination test is compared with the well-known Fisher method of combining tests. It is shown by a Monte Carlo study that the linear combination test has a larger power.     

A Mission of Civic Engagement: Undergraduate Students Working with Nonprofit Organizations and Public Sector Agencies to Enhance Societal Wellbeing

Universities in the U.S. have been criticized for not contributing enough to the social well-being of the communities within which they operate, and business schools have been accused of failing to prepare students adequately for careers in business. These criticisms have led to increased focus on service learning, a form of experiential learning that aids students in the application of theoretical knowledge to “real-life” situations—including problems and opportunities—faced by local as well as international communities. Even though service-learning has become fairly popular in business schools throughout the U.S., there is relatively little literature that illuminates its application. Thus, the present article describes a service-learning project in a marketing research course and how this project supports the university’s mission of civic engagement. Included are also a discussion of course-specific objectives as well as learning goals, objectives, and assessments as commonly required by regional and national accreditation agencies.     

The Relationship Between Hope,Eustress, Self-Efficacy,and Life Satisfaction Among Undergraduates

The construct of eustress was studied alongside hope and self-efficacy, to explore how these constructs are related to life satisfaction among undergraduates. Questionnaires were administered to undergraduates to test the hypotheses that (1) as eustress levels increase, so will life satisfaction levels; (2) when eustress, hope, and self-efficacy are examined together, they will predict life satisfaction better than eustress alone; (3) eustress, hope, and self-efficacy will all be positively correlated with life satisfaction; and (4) self-efficacy will be the most positively correlated with life satisfaction. The results revealed a significant positive correlation between eustress and life satisfaction. A Hierarchical Linear Regression analysis revealed significant results supporting hypotheses 2 and 3, but not hypothesis 4. Results indicated that hope is the best predictor of life satisfaction. The work reported provides a reliable tool for measuring eustress, examines eustress in a new way at the academic level, and provides helpful information about student wellness to college administrators.     

Determining the effects of intraclass correlation on factorial experiments

This paper considers the effects of the presence of eqmi-correlation between observations in a k-way factorial experiment, A technique to provide unbiased F-tests is also constructed.